Page allocator doesn't keep migratetype information to page
when the page is freed. This patch remains the information
to freed page's index field which isn't used by free/alloc
preparing so it shouldn't change any behavir except below one.
This patch adds a new call site in __free_pages_ok so it might be
overhead a bit but it's for high order allocation.
So I believe damage isn't hurt.
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
include/linux/mm.h | 6 ++++--
mm/page_alloc.c | 7 ++++---
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 86d61d6..8fd32da 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -251,12 +251,14 @@ struct inode;
static inline void set_page_migratetype(struct page *page, int migratetype)
{
- set_page_private(page, migratetype);
+ VM_BUG_ON((unsigned int)migratetype >= MIGRATE_TYPES);
+ page->index = migratetype;
}
static inline int get_page_migratetype(struct page *page)
{
- return page_private(page);
+ VM_BUG_ON((unsigned int)page->index >= MIGRATE_TYPES);
+ return page->index;
}
/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 103ba66..32985dd 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -723,6 +723,7 @@ static void __free_pages_ok(struct page *page, unsigned int order)
{
unsigned long flags;
int wasMlocked = __TestClearPageMlocked(page);
+ int migratetype;
if (!free_pages_prepare(page, order))
return;
@@ -731,9 +732,9 @@ static void __free_pages_ok(struct page *page, unsigned int order)
if (unlikely(wasMlocked))
free_page_mlock(page);
__count_vm_events(PGFREE, 1 << order);
- free_one_page(page_zone(page), page, order,
- get_pageblock_migratetype(page));
-
+ migratetype = get_pageblock_migratetype(page);
+ set_page_migratetype(page, migratetype);
+ free_one_page(page_zone(page), page, order, migratetype);
local_irq_restore(flags);
}
--
1.7.9.5
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